Core catcher



y J. s. eoopwm v 2,471,616

CORE GATCHER Filed April 10, 1945' .d mw

Arm/MEY- Patented May 31, 1949 UNIT!) STATS ATENT OFFICE CORE CATCHER John S. Goodwin, Whittier, (Jaliicl, assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application April 10, 1945, Serial No. 587,453

6 Claims.

This invention relates to core catchers and relates more particularly to core catching and mounting means for embodiment in a well tool. An object of my invention is to provide a simple, practical and effective core catcher for a well drill or a well core drill which is positive and dependable in operation.

Another object of my invention is to provide a well tool in which a core catcher, embodied in a core drill, has a maximum feasible core opening whereby the capacity of the tool is as great as possible.

Another object of my invention is to provide a well drilling tool incorporating a core catcher of extremely large capacity as related to the size of the drilling bit of said tool whereby said tool is enabled to function as a fishing tool or junk catcher of extremely large capacity.

Another object of my invention is to provide a well drilling tool incorporating a core catcher and adapted for use as a fishing tool for catching both small and relatively large items or junk lost in the well.

Another object of my invention is to provide a tool of the character indicated which has a core catcher of such relatively large size as to enable the tool to take a core which could only be taken previously by an oversize head spring type catcher, and yet enable the tool to fish and hold small items previously handled by a regular head with dog type catchers.

A further object of my invention, therefore, is to obviate the need for different types and sizes of tools for coring or for fishing and to provide one tool capable of performing the work of said different types and sizes of tools with resultant economy and saving of time.

A further object of my invention is to provide a core catcher in which the structural details and their arrangement are of novel design and form enabling the provision of an extremely large core catcher in a core bit of regular size and in which the parts are sturdy, strong and wearresistant to a high degree.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a longitudinal broken elevational view in quarter section of a core drill embodying my invention.

Fig. 2 is a cross sectional view taken as indicated by the line 2-2 of Fig. 1.

Fig. 3 is an enlarged fragmentary cross sectional view taken as indicated by the line 3-3 of Fig. 1.

Figs. 4 and 5 are fragmentary vertical sectional views taken as indicated by the lines 6-4 and 5-5 of Fig. 3, respectively.

The core catcher of my invention is adapted to be embodied in or applied to core drill or coring devices of various types. In the following detailed specification I will disclose a typical preferred form of the invention embodied in a typical core drill, it being understood that the invention is not intended to be limited or restricted to the specific form or application described, but is to be considered as including such features or modifications which may fall within the scope of the invention as claimed.

The drawing illustrates a single barrel core drill involving the invention and which may be said to comprise, generally, a barrel II], a bit head H carried by the barrel l0 and respective upper and lower core catcher units 12 and I? carried by the bit head II, and each having retractable fingers or dogs.

The barrel I0 is adapted to be attached to the lower end of an operating string of drill pipe or the like, and to receive the core cut by the bit head H. The barrel is a generally tubular member which may be of any desired length. In accordance with the usual practice, the barrel It may be provided at its upper end with a threaded box M for receiving a mating pin on the lower end of a string of drill pipe. Said upper end l5 of the barrel I0 is shown as smaller in diameter than the remaining elongated portion l6 of the barrel. A central longitudinal opening I! is provided in said portion [6 for receiving the core cut by the drill, said opening I! having connection with the box l4 by means of a smaller aligned opening I8. The lower end of the barrel portion is somewhat reduced in diameter to pro vide an annular shoulder I9 and said reduced end is externally threaded as at 2B.

The bit head I I is operable to make an annular cut in the earth formation to form a core to be received by the barrel l0. Said bit head i l comprises a tubular member 21 having internal threads 22 for connection with the threaded end 25 of the barrel ill and engaged with the shoulder i9 thereof to form a rigid extension of said barrel. The lower end of the bit head H is provided with an inreaching annular flange 23 defining a central cylindrical opening 24 which, in the present case, approximates the opening I? in size and is longitudinally aligned therewith. The bit head II,

3 between the flange 23 and the bottom end of the barrel it, has an opening 25, larger in diameter than either opening I! or 24, providing a connecting chamber for said openings l1 and 24 in which the core catcher units I2 and I3 are located. The bit head II is provided with earth formation cutting parts 26. Generally, and in a conventional manner, the cutting parts 26 comprise integrally connected cutting blades on the tubular member H which project outwardly and downwardly from the lower end of said tubular member. The cutting blades 26 are spaced apart circumferentially and disposedflto make an annular out in the earth formation and to form.

a core which is adapted to pass into the chamber and into the opening I1 with suitable clearance. I

Generally, the above-described core drill comprising the barrel Ill and the bit head II, is of conventional form. However, the proportion and arrangement of the parts have been designed. with the view of providing a core drill particularly suitable for the present invention. It will be noted that the barrel .IU comprises a, single element of strong and easily manufactured design. whereas, heretofore, the barrel was made. of several parts such as barrel, tubes, subs, adapters, etc. Byineans of the constructionwhich I have provided, the openings I I and 24 and the chamber 25 can beand are extremelylarge, diametrally, with relation to the size. of the. .tool .as awhole.

By means of my construction, the tubular mern ber- 2i can have. a. relatively thin. yet strong tubular outer wall. whereby themaximum practical diameter of the-chamber25 is aiforded. Accordingly, I am enabled to make thecore receiving openings 24 and I.1, .commensurately large. When the above-described tool is lowered intoa well bore, the cutters 26 penetratethe forma tionleaving-a core which is receivedin the aligned openings 24 and I1 .andchamber 25;

The tool which I-have provided; in addition-to functioning as a core catcher, can be advantageously used as a; finishing tool or junk catcher. Accordingly, I provide the upper core; catcher unit I2 for the primary purpose of breaking out the core which is formed by the tool and the lower core catcher unit I3 forthe-prirnary purpose of engaging items which may'be lost in, thewell and which may vary greatly in size, Generally, I provide each unit I2 and I3 .withqa plurality of inreaching radially disposed retractable fingers or dogs, the dogs-30 and 3I. of the upper unit ['2' being generally. shorter thanthe dogs 32 and 33 of the lower unit I3. The dogs of the upper unit 52, when unretracted', extend toward the center of the chamber 25=-but --'fall short thereof to leave a relatively large central opening3'4 between their inner ends. Both sets of dogs areupwardly retracted by the core as it enters the chamber 25. The units I2 and I3 are essen'tially the same with the exception of the lengths of their respective dogs and with the further exception that the unit I3 is higher or wider than the unit I2. Accordingly, the following description of the unit I3 will serve to describe the unit I2 also.

The unit I3 comprises an outer ring 35 having a cylindrical inner wall 4Iaand having an inreaching annular shoulder flange 36 at its lower end and a plurality-of uniformly spaced slotted openings 3'! extending upwardly from saidlower end. In this case the unit [3 carries five each of the dogs 32 and 33 and, therefore, has ten openings 31. Between two of the openings, the ring 35 is slit through from top to bottom as at 38. Within the ring 35, and resting upon the shoulder flange 36, there is provided an inner ring 39 of lesser height than the ring 35 and having an annular recess 49 at its lower end into which said shouider flange engages. The central opening or bore ii of the inner ring 39 approximates the passage 26 in size so that said opening forms a continuation of said passage. The inner ring 39 is formed with a plurality of slotted openings or notches 52 in register with the slotted openings or notches 3? in the outer ring. The openings 62, however, extend downwardly from the top edge of the. ring .35! and are, in part, co-extensive with the openings 37 to provide seats t3 for the dogs 32 and 33. Said seats 43 are each defined by the aligned or registered lateral walls of the registered notch-like openings 3'! and 42, by an upper slightly angled wall 44 of the opening 31, and by a lower also angled wall 45 of the opening 62. The ring 39 is further provided with a peripheral groove or channel :6 which extends between the dog seats 3. The rings 35 and 39 are secured together by rivets or the like, 4'! which I show arranged in two sets connecting the unslotted portions of the rings.

The dogs 32 and 33 are mounted in the seats 33 to extend radially inward. Each dog comprises an elongated member which is generally wedge-shaped from its relatively thin end 43 to its thicker portion iii adjacent a hole Ell in said dog for a pivot pin 5I engaged in the channel 46. Around the hole 5%, the dog is formed with a radius 52 extending tangentially from the under surface 53 of the dog toa lug 54 directed at an angle to the elongated portion of said dog. In the unretracted position of the dog, the portion of its surface 53 adjacent to the radius 52 engages the angled wall 35 and the lug 53 engages the opposed angled Wall M to provide two points of support for the dog on opposite sides of its pivot pin 5i. Each pivot pin 5| extends laterally of the dog which it mounts and into the channel 46. Accordingly, said extending ends of each pin are beveled as at 55 to conform with the circumferential curvature of the ring 35. By means of this structure the pins M are also prevented from being-dislodged laterally. I

It is apparent from the foregoing that as the tool forms a core, said core will progressively project into the chamber 25 and will retract the dogs 32 and 33 upwardly around their pivot pins 5!. From Fig. 4 it will be seen that I have designed the core catcher so that the dogs can be fully moved out of the path of the core to be entirely clear of said core. I have, therefore, arranged the upper surface 56 of each dog to intercept a radius 5'! equal to the radius 52 around the dog hole 5!) so that said dog surface 55 is enabled to lie flat against the inner surfaceof the ring 35. In this fully retracted position the dogs are clear of the core.

The dogs 32 and 33 are retractable against spring or similar means which seek to swing the dogs down to their inreaching position as determined by the angled walls 44 and 45. For this purpose, each dog is provided with a slot 58 between andparallel to the sides of the dog to bifurcate its pivot end. Within the slot 58 and around the pivot pin 5 I, I provide a coiled or twist spring 59 having one end 60 bearing on the ring 35 and the other end 6| bearing on the dog.

From the above structure it will be seen that side thrusts on the dogs are taken by the side walls of the openings 42 of the inner ring 39 and .5 that longitudinal loading forces, which act downwardly only, are taken by the assembled rings 35 and 39 at their angled walls i l and 45, the pins serving merely to hold the dogs in position. It will be further seen that because of the engagement of the flange 36 and the shoulder it], the rings 35 and 39 cannot separate axially in one direction, and because of the engagement of the dog lug 5 3 with the angled Wall 44, said rings cannot separate axially in the other direction.

The tool above-described, after forming a core which projects upward into the barrel passage H, can be operated to break out said core. This core breaking operation is performed by raising the tool so that the bit head i i is lifted from the formation at the bottom of the well bore. Since the springs 53 urge the retracted dogs inwardly, said dogs are forced progressively further into the core as the tool is rotated and the core can be readily broken loose from the formation by pulling upwardly on the tool. It is evident that the shortest dogs will more efficiently bite into the core because the change in the angular position is more rapid as said dogs are forced into the core. The other longer dogs 3!, 32 and 33, While less efficient as core cutters because of their greater length, function more efficiently as catchers for items lost in the well bore. I have, therefore, provided each dog with side bevels 62 for the purpose of providing cutting edges adapted to cut in the core and, in the case of the longest dogs 33, for the further purpose of obtaining the maximum length of said dogs 33 as best seen in Fig. 2.

Each of the units l2 and it are easily assembled. The dogs are first mounted on the ring 33, the split outer ring 35 is then sprung over the dogs, pulled into place, and riveted together as described. The catcher units thus provided afford maximum support for the dogs with minimum thickness of the rings 35 and 39 resulting in the ability of the tool to handle an extremely large core. Also, the flange 23 of the bit head fully supports the catcher unit is, and the latter in turn, fully supports the unit 12 when the tool is pulled upwardly to break the core. Further, the flange 35 of each unit takes the upward thrust of the tool as imparted to the ring 35 of each unit, to remove the shear on the rivets All.

Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described my invention, I claim:

1. Core breaking and catching means inclucling, a vertical external elongate ring having an inwardly directed annular shoulder flange at its lower end, a vertical internal ring of lesser height than the external ring arranged within the external ring and engaged with said shoulder flange, means connecting said rings, a plurality of seats comprising aligned notches formed in both rings, a plurality of like dogs, means pivotally mounting a dog in each seat, and resilient means engaging each dog and normally yieldingly holding it in position where it extends substantially radially of the rings and is inwardly directed from point of pivotal mounting.

2. Core breaking and catching means including, a vertical external split ring having an inwardly directed annular shoulder flange at its lower end, an internal ring of lesser height than the external ring arranged within the external ring and engaged with said shoulder flange, means connecting said rings, there being aligned notches formed in both rings establishing a plurality of circumferentially spaced seats, a plurality of like dogs, means pivotally mounting a dog in each seat, and resilient means engaging each dog and normally yieldingly holding the dog in a position Where it extends substantially radially of the rings and inwardly from its point of pivotal mounting.

3. In a core breaking and catching means, a vertical external ring having an internal cylindrical wall and a lower inwardly directed annular shoulder flange, an internal ring of lesser height and greater thickness than the external ring and located within the cylindrical wall of the external ring and engaged with said shoulder flange, the said external and internal rings having registering dog receiving notches, there being a pin carrying channel in the exterior of the internal ring, and means joining the rings together with said wall of the external ring closing said channel.

4. A core breaking and catching unit including, a vertical outer thin walled split elongate cylindrical ring having an inwardly directed annular shoulder flange at its lower end portion and a plurality of downwardly opening notches in its lower end portion, an inner ring arranged within the first mentioned ring and seated on said shoulder flange and having a wall thicker than that of the outer ring with a plurality of upwardly opening notches aligned with the first mentioned notches and in communication with the first mentioned notches to form a plurality of seats, the upper end of the inner ring terminating below the upper end of the outer ring, a plurality of tapered dogs, pivot pins held between the rings and pivotally mounting a dog in each seat, resilient means engaging each dog and normally yieldingly holding it in a position where it extends radially of the rings and inward toward the center of the unit, each dog being adapted to be retracted to assume a position with its upper side substantially parallel with the first mentioned ring while its lower side extends upwardly and outwardly, and means joining the rings together holding the dogs and pins.

5. A core breaking and catching unit including, an outer thin walled split elongate cylindrical ring having an inwardly directed annular shoulder flange at its lower end and a plurality of downwardly opening notches in its lower end, an inner ring seated on said shoulder flange and having a Wall substantially thicker than that of the outer ring and having a plurality of upwardly opening notches in its wall aligned with the notches of the outer ring to form a plurality of seats, said inner ring being formed with an annular outwardly faced circumferential groove interconnecting said seats and closed by the inner side of the wall of the outer ring, pivot pins in said groove retained therein by the inner ring and each extending across a seat, and a dog pivotally carried on each pivot pin and normally radially directed toward the center of the unit.

6. A core breaking and catching unit including an outer thin walled split elongate cylindrical ring having an inwardly projecting annular shoulder flange at its lower end and a plurality of downwardly opening notches in its lower end, an inner ring engaged in the outer ring and on said shoulder flange and having a plurality of upwardly opening notches aligned with the notches of the outer ring to form a plurality of ried on each pin, each dog being normally radially 10 directed inward toward the center of the unit and adapted to be retracted to assume a position where it extends upwardly so its outer side bears on and is substantially parallel to the inner wall of the outer rin while its inner side extends upwardly and outwardly.

JOHN S. GOODWIN.

8 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,464,239 Boynton Aug. 7, 1923 1,574,922 Nelson Mar. 2, 1926 1,663,702 Himes Mar. 27, 1928 2,054,278 Wright et a1. Sept. .15, 1936 2,115,166 Hoffoss Apr, 26, 1938 2,214,238 Stovall Sept. 10, 1940 2,258,352 Catland et a1 Oct. 7, 1941 2,326,209 Egerss Aug. 10, 1943 

